1. Field of the Invention
The present invention relates to an antenna system, a transceiver, electrical equipment, and a computer terminal, and more particularly to devices capable of corresponding to transmitting and/or receiving radio waves in a plurality of frequencies.
2. Description of the Related Art
Published Unexamined Japanese Patent Applications Nos. 10-276033 and 11-168323 disclose antenna systems which decrease in size by forming a conductive portion of an antenna at both faces of an insulating substrate as a conductive film. That is, in the case of the disk monopole antenna in Published Unexamined Japanese Patent Application No. 10-276033, circular conductive films of a radio-wave resonant portion and a ground portion are formed at both faces of an insulating substrate so as to shift from each other when viewed from a direction vertical to the insulating substrate. Moreover, dipole elements of the logarithmically periodic dipole antenna in Published Unexamined Japanese Patent Application No. 11-168323 are formed at both faces of an insulting substrate so as to extend in directions opposite to one another from two parallel lines.
In the case of the antennas in Published Unexamined Japanese Patent Applications Nos. 10-276033 and 11-168323, it is disclosed that elements of each of the antennas are distributed at both faces of an insulating substrate and that one antenna is comprised of the elements distributed at both faces. In the case of antenna systems in Published Unexamined Japanese Patent Applications Nos. 10-276033 and 11-168323, to form a plurality of antennas on a common insulating substrate, it is desirable to arrange the antennas on the insulating substrate so as each antenna does not overlap with each other antenna when viewed from a direction vertical to the insulating substrate. For example, to set two antennas to a common insulating substrate, the size of the insulating substrate is doubled as compared with the case of setting one antenna to the insulating substrate.
It is an object of the present invention to provide an antenna system, a transceiver, electrical equipment, and a computer terminal respectively decreased in size.
In one aspect of the present invention, an antenna system is comprised of:
an insulating substrate having a first antenna-only area and a second antenna-only area, wherein the first area and the second area are configured to overlap with each other when viewed from a direction vertical to a face from both of the side faces,
a first antenna having a conductive film in the first antenna-only area of the insulating substrate and which acts as an antenna for transmitting and/or receiving radio waves of a first frequency, and
a second antenna having a conductive film in the second antenna-only area of the insulating substrate and which acts as an antenna for transmitting and/or receiving radio waves of a second frequency which is lower than the first frequency.
As used herein, the term xe2x80x9cAntenna-only areaxe2x80x9d is defined to include a range of a convex polygon of a necessary minimum area including all elements of an antenna. Antenna elements include not only a ground portion and a conductive film such as x5, but also include a gap area formed between the ground portion and an x5.
First and second antennas are not restricted to transceiving antennas as each may be a transmission-only antenna or a reception-only antenna. Moreover, in another aspect of the present invention either the first or the second antenna may be used as a transmission-only antenna whereby the other antenna would act as a reception-only antenna. The Standards as used in the present invention also include those of a wireless LAN such as 802.11b and 802.11a, wherein 2.45 GHz and 5.2 GHz are radio frequencies used for 802.11b and 802.11a. In another aspect of the present invention, a first antenna and a second antenna may be used in conjunction with separate frequencies of a wireless LAN, that is, a frequency for 802.11b and a frequency for 802.11a, respectively. Moreover, because the frequency of 802.11b is almost equal to a that of a Bluetooth frequency, it is possible to use the frequency of a first antenna and that of a second antenna for Bluetooth and 802.11a.
Thus, it is possible to arrange a first antenna and a second antenna in first and second antenna-only areas of each face of an insulating substrate and decrease an antenna system having a plurality of antennas in size because the first antenna-only area and the second antenna-only area at least overlap with each other when viewed from a direction vertical to a face of the insulating substrate.
In the case of an antenna system of a predetermined mode, a first antenna-only area is included in a second antenna-only area when viewed from a direction vertical to a face of an insulating substrate.
In the case of the antenna system of the predetermined mode, first and second antennas are respectively provided with a radio-wave resonant portion and a ground portion extending in parallel with each other and the ground portions of the first and second antennas almost overlap with each other when viewed from a direction vertical to a face of an insulating substrate. The antenna system of the predetermined mode has a plurality of ground vias for connecting the ground portions of the first and second antennas distributed in the range of the ground portions of the antennas each other.
According to the antenna system of the predetermined mode, the first and second antennas are respectively provided with a radio-wave resonant portion and a ground portion extending in parallel with each other and the radio-wave resonant portions of the first and second antennas are arranged so as not to overlap with each other when viewed from a direction vertical to a face of an insulating substrate. The antenna system of the predetermined mode has a feed via whose one end is located outside of the radio-wave resonant portion of the antenna at the one-end side and whose other end is located inside of the radio-wave resonant portion of the antenna at the other-end side and a conductive portion for electrically connecting one end of the feed via to a predetermined position of the radio-wave resonant portion of the antenna at the one-end side.
According to the antenna system of the predetermined mode, the first and second antennas are slot antennas or inverted-F-type antennas. According to the antenna system of the predetermined mode, the radio-wave resonant portions of the first and second antennas are provided with radio-wave resonant portions and ground portions extending in parallel with each other, when viewed from a direction vertical to a face of an insulating substrate, the ground portions of the first and second antennas almost overlap with each other, and the radio-wave resonant portion of the first antenna is set between the radio-wave resonant portion and ground portion of the second antenna so as not to overlap with the radio-wave resonant portion of the second antenna.
A transceiver of the present invention has the following:
an insulating substrate having first and second antenna-only areas at least overlapping with each other when viewed from a direction vertical to a face from both of the side faces;
a first antenna whose element is formed by a conductive film in the first antenna-only area of the insulating substrate as an antenna for transmitting and/or receiving radio waves of a first frequency;
a second antenna whose element is formed by a conductive film in the second antenna-only area of the insulating substrate as an antenna for transmitting and/or receiving radio waves of a second frequency lower than the first frequency;
a ground via for connecting ground portions of the first and second antennas each other;
a feed via for connecting feed points at the radio-wave resonant portions of the first and second antennas each other;
a feed cable whose ground line and feed line are connected to the feed via and the ground portion of the first or second antenna, respectively; and
a frame ground member connected to the ground portion of the first or second antenna.
The feed cable includes not only a coaxial cable but also a Lecher wire, a microstrip, and a waveguide. As used herein, the term xe2x80x9cFrame groundxe2x80x9d is a used to point portions of ground potentials of various electrical equipment (including a computer terminal).
A transceiver of a predetermined mode has first signal-processing means for a first antenna, second signal-processing means for a second antenna, and selection means for selecting either of the first and second signal-processing means and connecting the selected signal-processing means to a feed cable.
Electrical equipment of the present invention uses a transceiver. The transceiver used includes not only transceivers already described but also the following transceivers. That is, the transceiver has an insulating substrate having first and second antenna-only areas at least overlapping with each other when viewed from a direction vertical to a face at the both side faces respectively, a first antenna whose element is formed of a conductive film in the first antenna-only area of the insulating substrate as an antenna for transmitting and/or receiving radio waves of a first frequency, a second antenna whose element is formed of a conductive film in the second antenna-only area as an antenna for transmitting and/or receiving radio waves of a second frequency lower than the first frequency, a ground via for connecting ground portions of the first and second antennas each other, a feed via for connecting feed points of the radio-wave resonant portions of the first and second antennas each other, a feed cable whose ground line and feed line are connected to the feed via and the ground portion of the first or second antenna, first signal-processing means for the first antenna, second signal-processing means for the second antenna, and selection means for selecting either of the first and second signal-processing means and connecting the selected signal-processing means to the feed cable.
Electrical equipment includes AV (Audio and Visual) equipment and electrical home appliances such as a microwave oven and a full-automatic washing machine.
A computer terminal of the present invention has a body equipped with an operational section, a cover equipped with a display to cover the body at a closed position, and a hinge member for connecting the body with the cover so that the cover swings against the body between its closed position and open position. The cover includes an insulating substrate having first and second antenna-only areas at least overlapping with each other when viewed from a direction vertical to a face at the both side faces respectively, a first antenna whose element is formed by a conductive film in the first antenna-only area of the insulating substrate as an antenna for transmitting and/or receiving radio waves of a first frequency, a second antenna whose element is formed by a conductive film in the second antenna-only area of the insulating substrate as an antenna for transmitting and/or receiving radio waves of a second frequency lower than the first frequency, a ground via for connecting ground portions of the first and second antennas each other, a feed via for connecting feed points at the radio-wave resonant portions of the first and second antennas each other, and a feed cable whose ground line and feed line are connected to the feed via and the ground portion of the first or second antenna.
The computer terminal may include any of a notebook-type PC (Personal Computer), a PDA (Personal Digital Assistant: portable information terminal unit), and/or a game terminal. The operational section denotes a key arrangement section.
A computer terminal of a predetermined mode has first signal-processing means for a first antenna, second signal-processing means for a second antenna, and selection means for selecting either of the first and second signal-processing means and connecting the selected signal-processing means to a feed cable. It is preferable that these first and second signal-processing means and the selection means are included in the body.
According to the computer terminal of the predetermined mode, a hinge member has a conductive rotary shaft and conductive body-side hinge and cover-side hinge which are rotatable about the axis of the rotary shaft and which combine with the body and cover and rotate together, the cover-side hinge extends up to the vicinity of the front end of the cover far from the rotary shaft, and an antenna system includes an insulating substrate, and first and second antennas and is set to the cover-side hinge so that it face-contacts the vicinity of the front end of the cover-side hinge at the ground portions of the first and second antennas but it does not contact the cover-side hinge at radio-wave resonant portions of the first and second antennas. In the case of the computer terminal of the predetermined mode, the rotary shaft of the hinge member and the body-side hinge and cover-side hinge respectively serve as a ground frame.